Clavicle Fractures

Authors: Koval, Kenneth J.; Zuckerman, Joseph D.

Title: Handbook of Fractures, 3rd Edition

Copyright ©2006 Lippincott Williams & Wilkins

EPIDEMIOLOGY

• Clavicle fractures account for 2.6% to 12% of all fractures and for 44% to 66% of fractures about the shoulder.
• Middle third fractures account for 80% of all clavicle fractures, whereas fractures of the lateral and medial third of the clavicle account for 15% and 5%, respectively.

ANATOMY

• The clavicle is the first bone to ossify (fifth week of gestation) and the last ossification center (sternal end) to fuse, at 22 to 25 years of age.
• The clavicle is S-shaped, with the medial end convex forward and the lateral end concave forward.
• It is widest at its medial end and thins laterally.
• The medial and lateral ends have flat expanses that are linked by a tubular middle, which has sparse medullary bone.
• The clavicle functions as a strut, bracing the shoulder from the trunk and allowing the shoulder to function at optimal strength.
• The medial one-third protects the brachial plexus, the subclavian and axillary vessels, and the superior lung. It is strongest in axial load.
• The junction between the two cross-sectional configurations occurs in the middle third and constitutes a vulnerable area to fracture, especially with axial loading. Moreover, the middle third lacks reinforcement by muscles or ligaments distal to the subclavius insertion, resulting in additional vulnerability.
• The distal clavicle contains the coracoclavicular ligaments.
  • The two components are the trapezoid and conoid ligaments.
  • They provide vertical stability to the acromioclavicular (AC) joint.
  • They are stronger than the AC ligaments.

MECHANISM OF INJURY

• Falls onto the affected shoulder account for most (87%) of clavicular fractures, with direct impact accounting for only 7% and falls onto an outstretched hand accounting for 6%.
• Although rare, clavicle fractures can occur secondary to muscle contractions during seizures or atraumatically from pathologic mechanisms or as stress fractures.

CLINICAL EVALUATION

• Patients usually present with splinting of the affected extremity, with the arm adducted across the chest and supported by the contralateral hand to unload the injured shoulder.
• A careful neurovascular examination is necessary to assess the integrity of neural and vascular elements lying posterior to the clavicle.
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• The proximal fracture end is usually prominent and may tent the skin. Assessment of skin integrity is essential to rule out open fracture.
• The chest should be auscultated for symmetric breath sounds. Tachypnea may be present as a result of pain with inspiratory effort; this should not be confused with diminished breath sounds, which may be present from an ipsilateral pneumothorax caused by an apical lung injury.

ASSOCIATED INJURIES

• Up to 9% of patients with clavicle fractures have additional fractures, most commonly rib fractures.
• Most brachial plexus injuries are associated with proximal third clavicle fractures.

RADIOGRAPHIC EVALUATION

• Standard anteroposterior radiographs are generally sufficient to confirm the presence of a clavicle fracture and the degree of fracture displacement.
• A 30-degree cephalad tilt view provides an image without the overlap of the thoracic anatomy.
• An apical oblique view can be helpful in diagnosing minimally displaced fractures, especially in children. This view is taken with the involved shoulder angled 45 degrees toward the x-ray source, which is angled 20 degrees cephalad.
• Computed tomography may be useful, especially in proximal third fractures, to differentiate sternoclavicular dislocation from epiphyseal injury, or distal third fractures, to identify articular involvement.

CLASSIFICATION

Descriptive

Clavicle fractures may be classified according to anatomic description, including location, displacement, angulation, pattern (e.g., greenstick, oblique, transverse), and comminution.

Allman

• Group I: fracture of the middle third (80%). This is the most common fracture in both children and adults; proximal and distal segments are secured by ligamentous and muscular attachments.
• Group II: fracture of the distal third (15%). This is subclassified according to the location of the coracoclavicular ligaments relative to the fracture:

Type I:	Minimal displacement: interligamentous fracture between the conoid and trapezoid or between the coracoclavicular and AC ligaments; ligaments still intact (Fig. 11.1)
Type II:	Displaced secondary to a fracture medial to the coracoclavicular ligaments: higher incidence of nonunion
IIA:	Conoid and trapezoid attached to the distal segment (Fig. 11.2)
IIB:	Conoid torn, trapezoid attached to the distal segment (Fig. 11.3)
Type III:	Fracture of the articular surface of the AC joint with no ligamentous injury: may be confused with first-degree AC joint separation (Fig. 11.4)

Figure 11.1. A type I fracture of the distal clavicle (group II). The intact ligaments hold the fragments in place. (From Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults, 4th ed, vol. 1. Philadelphia: Lippincott-Raven, 1996:1117.)

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• Group III: fracture of the proximal third (5%). Minimal displacement results if the costoclavicular ligaments remain intact. It may represent epiphyseal injury in children and teenagers. Subgroups include:

  Type I:	Minimal displacement
  Type II:	Displaced
  Type III:	Intraarticular
  Type IV:	Epiphyseal separation
  Type V:	Comminuted

  
  
  

  Figure 11.2. A type IIA distal clavicle fracture. In type IIA, both conoid and trapezoid ligaments are on the distal segment, whereas the proximal segment without ligamentous attachments is displaced. (From Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults, 4th ed, vol. 1. Philadelphia: Lippincott-Raven, 1996:1118.)

Figure 11.3. A type IIB fracture of the distal clavicle. The conoid ligament is ruptured, whereas the trapezoid ligament remains attached to the distal segment. The proximal fragment is displaced. (From Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults, 4th ed, vol. 1. Philadelphia: Lippincott-Raven, 1996:1118.)

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OTA Classification of Clavicle Fractures

See Fracture and Dislocation Compendium at http://www.ota.org/compendium/index.htm.

TREATMENT

Nonoperative

• Most clavicle fractures can be successfully treated nonoperatively with some form of immobilization.
• Comfort and pain relief are the main goals. A sling has been shown to give the same results as a figure-of-eight bandage, providing more comfort and fewer skin problems.
  
  
  

  Figure 11.4. A type III distal clavicle fracture, involving only the articular surface of the acromioclavicular joint. No ligamentous disruption or displacement occurs. These fractures present as late degenerative changes of the joint. (From Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults, 4th ed, vol. 1. Philadelphia: Lippincott-Raven, 1996:1119.)

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• The goals of the various methods of immobilization are as follows:
  • Support the shoulder girdle, raising the lateral fragment in an upward, outward, and backward direction.
  • Depress the medial fragment.
  • Maintain some degree of fracture reduction.
  • Allow for the patient to use the ipsilateral hand and elbow.
• Regardless of the method of immobilization utilized, some degree of shortening and deformity usually result.
• In general, immobilization is used for 4 to 6 weeks.
• During the period of immobilization, active range of motion of the elbow, wrist, and hand should be performed.

Operative

• The surgical indications for midshaft clavicle fractures are controversial.
• The accepted indications for operative treatment of acute clavicle fractures are open fracture, associated neurovascular compromise, and skin tenting with the potential for progression to open fracture.
• Controversy exists over management of midshaft clavicle fractures with substantial displacement and shortening (>1 to 2 cm).
  • Although most displaced midshaft fractures will unite, studies have reported shoulder dysfunction and patient dissatisfaction with the resulting cosmetic deformity.
• Controversy also exists over management of type II distal clavicle fractures.
  • Some authors have indicated that all type II fractures require operative management.
  • Others report that if the bone ends are in contact, healing can be expected even if there is some degree of displacement. In this situation, nonoperative management consists of sling immobilization and progressive range of shoulder motion.
• Operative fixation may be accomplished via the use of:
  • Plate fixation: This is placed either on the superior or the anteroinferior aspect of the clavicle.
    • Plate and screw fixation requires a more extensive exposure than intramedullary devices but has the advantage of more secure fixation.
    • Plate and screw fixation is more likely to be prominent, particularly if placed on the superior aspect of the clavicle.
  • Intramedullary pin (Hagie pin, Rockwood pin): This is placed in antegrade fashion through the lateral fragment and then in retrograde fashion into the medial fragment.
    • Use of intramedullary fixation requires frequent radiographic follow-up to monitor the possibility of hardware migration and a second procedure for hardware removal.
    • Intramedullary pins are prone to skin erosion at the hardware insertion site laterally.
  • Operative treatment of type II distal clavicle fractures consists of reducing the medial fragment to the lateral fragment. This is accomplished by using either coracoclavicular fixation (Mersilene tape, sutures, wires, or screws) or fixation across
    

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    the AC joint, through the lateral fragment and into the medial fragment.

COMPLICATIONS

• Neurovascular compromise: This is uncommon and can result from either the initial injury or secondary to compression of adjacent structures by callus and/or residual deformity.
• Malunion: This may cause an unsightly prominence, but operative management may result in an unacceptable scar.
  • The effect of malunion on functional outcomes remains controversial.
• Nonunion: The incidence of nonunion following clavicle fractures ranges from 0.1% to 13.0%, with 85% of all nonunions occurring in the middle third.
  • Factors implicated in the development of nonunions of the clavicle include (1) severity of initial trauma, (2) extent of displacement of fracture fragments, (3) soft tissue interposition, (4) refracture, (5) inadequate period of immobilization, and (6) primary open reduction and internal fixation.
• Posttraumatic arthritis: This may occur after intraarticular injuries to the sternoclavicular or AC joint.